ML15112B074
| ML15112B074 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/26/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML15112B073 | List: |
| References | |
| NUDOCS 8211060662 | |
| Download: ML15112B074 (2) | |
Text
UNITED STATES NAEAR REGULATORY COMMISSIONW WASHINGTON, D. C. 20555 ot SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.114 TO FACILITY OPERATING LICENSE NO. DPR-38 AMENDMENT NO.
114TO FACILITY OPERATING LICENSE NO.
DPR-47 AMENDMENT NO.
111TO FACILITY OPERATING LICENSE NO.
DOPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS NOS.
1, 2 AND 3 DOCKETS NOS. 50-269, 50-270 AND 50-287 Introduction Duke Power Company (Duke or the licensee) informed the NRC staff of problems with the pressurizer code safety valves at the Oconee Nuclear Staton on October 14, 1982.
Following a number of telephone conversations on this subject, Duke submitted an amendment application via telecopy, which requests that the requirements for these valves be w:;ved for Unit 1 until October 30, 1982 to allow time for the other Units (Units 2 and 3 were both' shutdown) to return to operation and to obtain replacement valves.- The problem with the valves occurs due to the positioning of the three, movable ring assemblies which control the lift setpoint and the blowdown capacity of the valve.
Following staff discussion and evaluation of the information provided by Duke in their October 14, 1982 application, it was decided that interim operation of Oconee Unit 1 was acceptable until 11:59pm on October 29, 1982. Our evaluation is presented below.
Duke was informed of our decision and given permission to continue operation of Oconee Unit 1 until 11159pm, October 29 on October 14, 1982; this permission was confirmed by letter dated October 15, 1982.
Evaluation The-licensee has proposed to operate Unit 1 for the period October 14, 1982 to October 29, 1982 with the-Reactor Coolant System (RCS) safety valves declared inoperable on the basis of the low probability of needing the safety valves and on an analysis of the limiting anticipated transients..'
and accidents which demonstrates that the RCS pressure limit of 2750 psig would not be exceeded for these events.
The low probability of challenging the safety valves is based on a review of operating experience for Babcock & Wilcox (B&W) and Westinghouse PWR's.
The estimate mean annual frequency for safety valve challenges is quoted as 4.8 x 10-.
This value is consistent w.ith the NRC staff's understanding of operating experience.
8211060662 8321026 PDR ADOCK 05000269 P
-2 The limiting events relative to overpressurization were reanalyzed by the licensee using the RELAP computer code and using the core physics parameters appropriate for the present time in core cycle. These analyses are summarized in the licensee's letter of October 14, 1982 and indicate that the peak RCS pressure would be less than 2750 psig.
These analyses are consistent with the Final Safety Analysis Report (FSAR) analyses which indicate that little safety valve discharge would be required to protect against a design basis accident.
Therefore, we find that even in the unlikely event that the RCS safety valves are called upon within the October 14, 1982 to October 29, 1982 period, the RCS pressure limit would not be exceeded as a result of degraded valve performance. As a result of our review, we find that operation in the proposed mode is acceptable.
Environmental Consideration We have determined that the amendments do not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having m-ade this determination, we have further concluded that the amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 651.5(d)(4), that an environmental impact statement, or negative declaration and environ mental impact appraisal need not be prepared in connection with the issuance of these amendments.
Conclusion We have concluded, based on the considerations discussed.above, that:
(1) because the amendments do not involve a significant increase in the probability or consequences of an accident previously evaluated, do not create the possibility of an accident of a type different from any evaluated previously, and do not involve a significant reduction in a margin of safety, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to-the common defense and security or to the health and safety of the public.
Dated: October 26, 1982 The following NRC personnel have contributed to this Safety Evaluation:
Philip Wagner, Gary Holahan.